FKIE_CVE-2026-89930
Vulnerability from fkie_nvd - Published: 2026-09-16 11:17 - Updated: 2026-09-16 15:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
KVM: nVMX: Service local TLB flushes on failed nested VM-Enter
KVM services local TLB flushes on "full" nested VM-Exits (through
__nested_vmx_vmexit()), but not if a nested VM-Enter fails (e.g. due to
failed VMCS checks in nested_vmx_enter_non_root_mode()).
However, it is possible that KVM had queued TLB flushes that need to be
performed, even if the nested VM-Enter was not successful. For example,
if VPID is disabled for L2 (via nested_vmx_transition_tlb_flush(), or if
via the MSR load lists, as the SDM says:
If any MSR is being loaded in such a way that would architecturally
require a TLB flush, the TLBs are updated so that, after VM entry, the
logical processor will not use any translations that were cached before
the transition.
The SDM is unclear about when the TLB flush should occur, and whether or
not a failed VM entry would flush the TLB, so it is safer to always
do the TLB flush in this case.
More concretely, KVM also updates the last VPID L1 used for L2 in
nested_vmx_transition_tlb_flush() (i.e. last_vpid), even if the VM entry
ultimately fails. With the current code, KVM could miss a TLB flush if
L1 changes L2's VPID, then does a failed VM entry followed by a
successful one, as the failed VM entry would update last_vpid but not
actually flush the TLB. Servicing local TLB flushes on failed VM entries
makes sure that the TLB is always flushed when last_vpid is updated.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"arch/x86/kvm/vmx/nested.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "c0c66cd575e31218da6a7d104c6ef80b0830b60c",
"status": "affected",
"version": "5c614b3583e7b6dab0c86356fa36c2bcbb8322a0",
"versionType": "git"
},
{
"lessThan": "1025b938dc439b75c720a568a855a13eeb245686",
"status": "affected",
"version": "5c614b3583e7b6dab0c86356fa36c2bcbb8322a0",
"versionType": "git"
},
{
"lessThan": "312cdb6d8940827dea63a7a52fb714a5049f06d1",
"status": "affected",
"version": "5c614b3583e7b6dab0c86356fa36c2bcbb8322a0",
"versionType": "git"
},
{
"lessThan": "f74fccdf4f7fb0780cd84944108d35f3d9dc46a7",
"status": "affected",
"version": "5c614b3583e7b6dab0c86356fa36c2bcbb8322a0",
"versionType": "git"
},
{
"lessThan": "c43563e7518e65ec6ccaa6a65f84c5af5ca5d379",
"status": "affected",
"version": "5c614b3583e7b6dab0c86356fa36c2bcbb8322a0",
"versionType": "git"
},
{
"lessThan": "62c3ee4c9f0e2efef5157358b3549e50ede96d73",
"status": "affected",
"version": "5c614b3583e7b6dab0c86356fa36c2bcbb8322a0",
"versionType": "git"
},
{
"lessThan": "05a0b701d1089fb57beeb8982f23c3bbafe0fa8b",
"status": "affected",
"version": "5c614b3583e7b6dab0c86356fa36c2bcbb8322a0",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"arch/x86/kvm/vmx/nested.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.4"
},
{
"lessThan": "4.4",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.221",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.188",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.157",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.110",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.51",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3-rc1",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: nVMX: Service local TLB flushes on failed nested VM-Enter\n\nKVM services local TLB flushes on \"full\" nested VM-Exits (through\n__nested_vmx_vmexit()), but not if a nested VM-Enter fails (e.g. due to\nfailed VMCS checks in nested_vmx_enter_non_root_mode()).\n\nHowever, it is possible that KVM had queued TLB flushes that need to be\nperformed, even if the nested VM-Enter was not successful. For example,\nif VPID is disabled for L2 (via nested_vmx_transition_tlb_flush(), or if\nvia the MSR load lists, as the SDM says:\n\n If any MSR is being loaded in such a way that would architecturally\n require a TLB flush, the TLBs are updated so that, after VM entry, the\n logical processor will not use any translations that were cached before\n the transition.\n\nThe SDM is unclear about when the TLB flush should occur, and whether or\nnot a failed VM entry would flush the TLB, so it is safer to always\ndo the TLB flush in this case.\n\nMore concretely, KVM also updates the last VPID L1 used for L2 in\nnested_vmx_transition_tlb_flush() (i.e. last_vpid), even if the VM entry\nultimately fails. With the current code, KVM could miss a TLB flush if\nL1 changes L2\u0027s VPID, then does a failed VM entry followed by a\nsuccessful one, as the failed VM entry would update last_vpid but not\nactually flush the TLB. Servicing local TLB flushes on failed VM entries\nmakes sure that the TLB is always flushed when last_vpid is updated."
}
],
"id": "CVE-2026-89930",
"lastModified": "2026-09-16T15:18:18.933",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 9.3,
"baseSeverity": "CRITICAL",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 2.5,
"impactScore": 6.0,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-09-16T11:17:02.290",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/05a0b701d1089fb57beeb8982f23c3bbafe0fa8b"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/1025b938dc439b75c720a568a855a13eeb245686"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/312cdb6d8940827dea63a7a52fb714a5049f06d1"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/62c3ee4c9f0e2efef5157358b3549e50ede96d73"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/c0c66cd575e31218da6a7d104c6ef80b0830b60c"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/c43563e7518e65ec6ccaa6a65f84c5af5ca5d379"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/f74fccdf4f7fb0780cd84944108d35f3d9dc46a7"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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